Evidenced-based airway management.

The increased polarity of evidenced-based medicine has changed the approach to evaluation of medical interventions and treatments, either placing them on firm scientific foundations or suggesting that evidence is inadequate to strongly support current or innovative practices. Airway management devices and techniques are essential and common components of clinical care. It is the purpose of this review to identify the levels of evidence that support common and novel techniques in airway management. Very few airway management techniques are supported by large, prospective randomized trials. In resuscitation, defibrillation should take priority over airway management. This is supported by animal studies and several reported series of patient experiences and will never be subjected to a prospective randomized trial. Substantial evidence supports the use of noninvasive ventilation, subglottic endotracheal tube secretion removal, changing ventilator circuits no more frequently than every 7 days, and the use of selective digestive decontamination with systemic antibiotics to reduce the incidence of ventilator-associated pneumonia. Little evidence supports using other measures such as elevating the head of the bed to 30% (but this costs nothing and is intrinsically attractive), use of heat and moisture exchangers, kinetic bed therapy, early tracheotomy, or lung secretion removal techniques to reduce ventilator-associated pneumonia. Percutaneous tracheotomy currently can only be recommended over open surgical tracheotomy based on cost, convenience and late stomal complications; it may be associated with a slightly higher morbidity and mortality.

Comparison of safety and cost of percutaneous versus surgical tracheostomy.

Tracheostomy continues to be a standard procedure for the management of long-term ventilator-dependent patients. Traditionally the procedure has been performed by surgeons in the operating theater using an open technique. This routine practice has recently been challenged by the introduction of bedside percutaneous dilatational tracheostomy (PDT), which has been reported to be a cost-effective alternative. The purpose of this study is to evaluate and compare the safety, procedure time, cost, and utilization of percutaneous and surgical tracheostomies at a university hospital. A retrospective medical chart review was performed on all ventilator-dependent intensive care unit patients at the University of Virginia Medical Center undergoing tracheostomy during a 23-month period beginning December 26, 1996. Of the 213 patients identified for review, 74 and 139 patients received percutaneous and surgical tracheostomies, respectively. Of 74 percutaneous tracheostomies, 73 reviewed were performed by general surgeons, pulmonary physicians, or anesthesiologists in the intensive care unit; all open tracheostomies were performed by surgeons in the operating room, and one percutaneous procedure was performed in the operating room. Perioperative complications occurred in five of 74 patients (6.76%) during PDT; of these, three patients (4.1%) experienced major complications requiring emergent operative exploration of the neck. Three patients (2.2%) experienced perioperative complications during surgical tracheostomy. The mean procedure time was significantly shorter for the percutaneous procedure. Average charges per patient in an uncomplicated case including professional fees, inventory, bronchoscopy (if performed), and operating room charges were $1753.01 and $2604.00 for percutaneous and standard tracheostomies, respectively. These charges do not include the charges associated with surgical intervention after PDT complications. In contrast to previously published reports showing complications clustered during a physician's first 30 percutaneous cases, our study demonstrated no relationship between complication occurrence and physician experience. That is, no learning curve associated with performing PDT was evident. In addition there was no association seen between physician specialty and complication rate. PDT in the intensive care unit costs less than surgical tracheostomy performed in the operating room and can be performed in less time. Several other studies have recommended that bronchoscopy during PDT provides additional safety; however, in our series all three major complications took place during bronchoscopy-assisted percutaneous procedures. Our series suggests that PDT carries an appreciable risk of major complications. Careful patient selection and additional experience with the procedure may decrease complication rates to an acceptable level.

A randomized, controlled, clinical trial of a chemically-reactive heated humidifier.

BACKGROUND: Inspired gases can be warmed and humidified in a variety of ways. The effect of a chemically-reactive heated heat and moisture exchanger/hygroscopic condenser humidifier (HME/HCH) on secretions, rate of core body warming, blood loss, and time to extubation was studied in hypothermic post-cardiac surgery patients. METHODS: Fifty patients with normal ventricular function, undergoing coronary bypass grafting, were randomized to receive either a conventional HME (Gibeck, Humid-Vent 1 [PN 11112], Hudson RCI, Temecula, California) or a chemically-heated HME (Thermax HCH Filter [PN 9302], Enternet Medical, Las Vegas, Nevada) following surgery or on arrival in the ICU. Effects on secretions, core temperature, postoperative bleeding, duration of intubation, and added resistance were measured. The Thermax weighs 67 g and adds 79 mL of dead space. The Humid-Vent 1 weighs 9.4 g and adds 10 mL of dead space. RESULTS: There was no significant difference between the 2 devices in time to extubation, blood loss, or quality or quantity of secretions. Use of the Thermax device, however, resulted in a more rapid rise in body temperature (0.299 degrees C/h with the Thermax vs 0.073 degrees C/h with the Humid-Vent 1, p = 0.001) and more added resistance (0.0672 cm H(2)O/L/s with the Thermax vs 0.0123 cm H(2)O/L/s with the Humid-Vent 1, p = 0.00000172). CONCLUSIONS: The Thermax chemically-heated HME results in more rapid warming of mildly hypothermic patients following cardiopulmonary bypass than does a conventional passive HME.

Initial experience with a respiratory therapist arterial line placement service.

BACKGROUND: Indwelling arterial lines are commonly used in critical care. To standardize and improve the placement of these devices, we developed and implemented a respiratory therapist-based line placement service. As a measure of the quality of the service, we assessed the success and complications encountered in the first 119 line placement attempts of this new service. METHODS: The following were recorded for each artery on which cannulation was attempted: the number of the attempt on which cannulation was successful; if a different person was able to cannulate the artery after initial failure; and whether any complications occurred. Success rate compared to the number of attempts was tested with chi-square. RESULTS: Respiratory therapists were successful in placing 80% of attempted lines on the first try, including all 18 of 18 dorsal pedis attempts. Ninety-seven percent (115 of 119) of attempted arteries were ultimately cannulated. Success on second attempts by the same person was less than if a different, more experienced, person attempted the placement (p = 0.024). No complications were identified during the study. CONCLUSIONS: Initiation of a respiratory therapist-based arterial line placement service resulted in an acceptable cannulation success rate, without complications. Increased experience of the person attempting cannulation correlates with improved success.

Therapist-driven protocols in adult intensive care unit patients.

TDPs occasionally are used to standardize or control respiratory management of the critically ill. Weaning protocols are most common. Little objective evaluation of the effects of TDPs in the critically ill has been published. Most protocols have been developed to improve efficiency of respiratory care staff and reduce unnecessary treatments in non-ICU patients. The most important reason for using TDPs in the ICU is to improve consistency of care. Reduction of variation between individual therapist style improves physicians' trust in the respiratory care department. Improved consistency may allow novel ICU therapies to be evaluated objectively. In general, TDPs are not directly transportable from one area or institution to another. TDPs require local development, and all interested parties must be part of the development process for success. The process of creating TDPs provides a forum for physicians, nurses, and therapists to establish mutual respect and understanding. The analytic approach needed to create useful TDPs provides a critical evaluation of unit procedures and promotes changes in care delivery extending outside the TDP. The complexity of disease process and patient care in the ICU makes comprehensive TDPs difficult to establish; however, use of computers for decision support can overcome the limitations of paper flow charts. Even without comprehensive TDPs, the development process is important to improving and understanding care of the critically ill. The effects of TDPs on ICU patient outcome are unknown currently. Benefits are possible and improved collaboration, better respiratory care staff morale, consistency of approach to care, and critical approach to clinical decision making can be gained by attempting to develop TDPs for respiratory care delivery in the ICU.

Comparison of APACHE II scoring in liver and kidney transplant recipients versus trauma and general surgical patients in a single intensive-care unit.

Over a 26-month period we assessed the ability of APACHE II, scored on admission to the surgical intensive care unit (SICU), to predict the in-hospital mortality of liver and kidney transplant recipients either post-operatively or after subsequent complications, and compared these results to non-transplant SICU admissions. There were 866 SICU admissions, of which 128 were liver transplant recipients, 112 were renal transplant recipients, 211 were trauma admissions and 415 were non-transplant/non-trauma admissions. In hospital mortalities among all liver transplant admissions were 0%, 10%, 38%, and 82% for APACHE II ranges of 0-10, 11-20, 21-30 and > 30, respectively, with differences between the second and third, and third and fourth ranges significant (p < or = 0.05 by chi-square analysis). These differences were also seen when examining scores following the primary transplantation alone. Mortalities in corresponding APACHE II ranges for trauma and nontransplant/nontrauma admissions were similar. APACHE II scoring was not useful for renal transplant recipient, as it consistently overpredicted mortality. We conclude that APACHE II scoring may be useful in predicting outcome in post-operative liver transplant recipients, but is not useful in stratifying risk in renal transplant recipients due to the inherently low mortality involved.

Sedation of the agitated, critically ill patient without an artificial airway.

One of the most demanding and stressful situations is management of the agitated, unintubated, critically ill patient. Sedation often must be provided without a specific diagnosis, and the need for rapid airway control must be anticipated. No predictably safe and effective techniques are proven. The experience and skill of the physician managing the patient during sedation are the predictive factors for the best outcome. Even in expert hands, airway compromise and cardiovascular decompensation often occur in these very ill patients. Many techniques for sedation have been described. Treatment of pain followed by small boluses of intravenous sedative agents is a reasonable initial approach. Benzodiazepines have a good safety record and provide good amnesia. Other agents have been used, by themselves or in combination. Haloperidol may have a therapeutic advantage in the disoriented, agitated patient. Prolonged need for significant sedative medication usually mandates a secure airway. Once this is accomplished, the requirement for a continuously present airway expert at the bedside is removed. The standard for sedating a patient without an artificial airway requires a higher level of expertise than sedating a critically ill patient with an artificial airway.

Can bacteremia be predicted in surgical intensive care unit patients?

OBJECTIVES: To determine which clinical features are associated with bacteremia in a SICU. To determine if infections are identified prior to bacteremia via culturing of other body fluids. To determine if antibiotic regimens are changed after the results of the blood culture were obtained. DESIGN: A retrospective, unit-based, case control study. SETTING: A 10 bed SICU in a 552-bed, tertiary care and Level I Trauma center. PATIENTS: All SICU patients with one or more positive blood cultures over a 2 year period (n = 24) were matched by diagnosis, procedure, and age to SICU patients with negative blood cultures (n = 48). MEASUREMENTS AND RESULTS: Bacteremic and control patients had similar APACHE II scores though death was more likely in bacteremic patients (p < 0.05) and they had higher hospital charges (p < 0.02). There was no difference in any of the clinical variables studied (minimum and maximum temperature, maximum white blood cell count, minimum mean arterial blood pressure) between the bacteremic and control groups on the days leading up to and the day of the positive blood culture. Coincident infections of lung, bladder, wound, and central venous catheters were identified in 42% of bacteremic patients. The identification of organisms found in the blood had a direct impact on the antibiotic regimen of 54% of the bacteremic patients. CONCLUSIONS: A better screen for obtaining blood cultures in this SICU was not identified. If antibiotics are begun empirically before the results of blood cultures are known, the results of other body fluid cultures can be used to guide therapy initially. However, the data obtained from positive blood cultures was often helpful in changing empirical therapy. Therefore, blood cultures remain important diagnostic tools.

Sedation in the critically ill patient.

Critically ill patients experience many unpleasant and frightening events while in an ICU. Appropriate concern for pain, discomfort, and anxiety is required from caregivers. The use of reassuring mannerisms, honest communication, and analgesics and sedatives, especially during therapeutic paralysis, improves patient comfort and reduces the morbidity rate. This article reviews the therapeutic options for sedation and experience with these agents in the critically ill.